Thank you all very much!!
This is exactly what i need to know.
In my architecture i will simply daisy chain a pdi cable from my last lcs switch module to a lcs serial module then use the mth cable to connect the tiu. I had previously removed the mth cable to connect the lcs db9/power/pdi cable to the cab2 unit.
Then i can run both mth and lionel trains from my mth handheld if i want. I did get my lcs wifi and ipad controlling the layout today with 4 switches. I will add 4 more switches tomorrow and order a serial module. At one point the wifi connection on the ipad application was unstable but i have to use it more to see if that will be a persistant problem
Thanks again to all.
Mike